fscanf (GNU Gnulib)

Gnulib module: stdio-h, nonblocking

Portability problems fixed by Gnulib module stdio-h, together with module nonblocking:

When reading from a non-blocking pipe whose buffer is empty, this function fails with errno being set to EINVAL instead of EAGAIN on some platforms: mingw, MSVC 14.

Portability problems not fixed by Gnulib:

C99 and POSIX.1-2001 and later require end-of-file to be sticky, that is, they require this function to act as if it reads end-of-file if feof would return nonzero. However, on some systems this function attempts to read from the underlying file descriptor even if the stream’s end-of-file indicator is set. These systems include glibc and default Solaris.
This function does not support size specifiers as in C23 (w8, w16, w32, w64, wf8, wf16, wf32, wf64) on some platforms: glibc 2.38, musl libc, macOS 14, FreeBSD 13.2, NetBSD 10.0, OpenBSD 7.2, AIX 7.2, HP-UX 11, Solaris 11.4, Cygwin 2.9.0, mingw, MSVC 14.
On Windows platforms (excluding Cygwin), this function does not set errno upon failure.
On Windows, this function doesn’t support the hh, ll, j, t, z size specifiers.